Palestinians clashed with Israeli police on Monday as the occupied territories marked the 69th anniversary of the "Nakba", or "day of catastrophe" when Israel officialy declared itself a state after the forced removal of more than 750,000 Palestinians.

Injuries were reported in the flashpoint West Bank town of Bethlehem, where Palestinians threw stones at Israeli police, who responded with tear gas. Palestinians also clashed with police near the illegal Jewish settlement of Beit El, near the West Bank city of Ramallah.

Palestinians in Israel, the occupied West Bank and the Gaza Strip were holding rallies, marches and candlelight vigils, on the same day Israel commemorates its "independence".

Sirens wailed in the West Bank to mark the passing of 69 years. Cars stopped and pedestrians stood still in commemoration.

Monday also marks the 29th day of a hunger strike by 1,500 Palestinians in Israeli prisons.

Imprisoned Palestinian leader Marwan Barghouti, who is a leader of the strike, released a statement through his lawyer on Sunday denying that a recent video released by Israeli prison authorities claiming to show him eating in his cell was fake, and the cell shown in the video was much larger and cleaner than his own.

"I plan to escalate my hunger strike soon. I will stop drinking water," Barghouti was reported to have said. "There is no backtracking. We will continue until the end."

Palestinian negotiator Saeb Erekat, who participated in the Oslo Accords to create a two-state solution to occupation, demanded an Israeli apology over the Nakba.

"Our nation marking 69 years of the Nakba, our national catastrophe, is symbolised in our exile and the systematic denial of our rights," Erekat said in a statement.

Palestinian survivors of the Nakba and their descendants have lived outside of Palestine since 1948, with millions of them still stateless or languishing in surrounding refugee camps.

Israel has prevented them from returning to their homes. Palestinians have cited UN Resolution 194 that they say preserves their "Right to Return" to Palestine.